Self-reporting is a common method used by dietitians, medical professionals, and researchers to evaluate individuals’ diets and their impact on health. However, self-reported data can often be inaccurate, posing a challenge in assessing dietary patterns effectively.
To overcome these limitations, researchers have turned to analyzing metabolites in blood as potential biomarkers for assessing dietary intake. Metabolites are molecules produced during metabolic processes, such as amino acids and peptides, that can provide objective insights into the foods we consume.
Andrea J. Glenn, assistant professor of nutrition at NYU Steinhardt School of Culture, Education, and Human Development, highlights the potential of using metabolites in blood as biomarkers for dietary patterns. By analyzing metabolites in controlled feeding studies, researchers aim to accurately gauge individuals’ adherence to specific diets.
The research focused on analyzing metabolites in plasma samples from participants in two trials following the portfolio diet, a plant-based diet designed to lower cholesterol levels through the consumption of foods like soy protein, nuts, plant sterols, and viscous fiber. Participants were provided with the designated foods for four weeks, with plasma samples collected at various intervals throughout the trials.
In the first trial, involving 34 participants across different diet groups, significant changes in 29% of known metabolites were observed in the portfolio diet group. The second trial, with 25 participants, showed significant changes in 12% of metabolites with the portfolio diet.
Overall, 10% of metabolites exhibited significant changes across both trials, indicating shifts in metabolites associated with plant-based diets and reduced saturated fat intake. These changes included increases in metabolites like N2-acetylornithine and lenticin, as well as decreases in C:18 lipids.
While these findings are promising for using metabolites as objective biomarkers for dietary assessment, further research is needed to validate their effectiveness. Glenn, the lead author of the study, emphasizes the importance of conducting additional studies to confirm the role of metabolites in evaluating adherence to specific diets.
More information:
Glenn, A.J., et al. Metabolomic profiling of a cholesterol lowering plant-based diet from two randomized controlled feeding trials, European Journal of Clinical Nutrition (2025). DOI: 10.1038/s41430-025-01625-x, www.nature.com/articles/s41430-025-01625-x
